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Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9746

Posted: 01:11pm 11 May 2017

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Hi folks.

What do the rest of you guys use for your soldermask offset?

I am not going to tell you what I use, till I get some feedback on what others use, cos I want to know those figures without my ones being known - yet.

I am looking for the best offset, with the tightest soldermask-to-pad clearance, that still works reliably at manufacture without overlaying the soldermask onto the pad you need to solder to.

We could consider this a game of sorts - Who can guess what I use?

EDIT: Rob(ert Rozee) - You are not allowed to guess, as you already know because of our emails on this subject.

Edited by Grogster 2017-05-12

Smoke makes things work. When the smoke gets out, it stops!

bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2971

Posted: 04:36pm 11 May 2017

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Grogs,

When you say "soldermask offset" I assume you mean the clearance from a pad etc?

My boards are done with a 0.004" (roughly 0.1mm) clearance.

So a pad of say 0.1" diameter would have a solder mask diameter of 0.108" (giving 0.004" clearance all around)

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

Grogster

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Location: New Zealand
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Posted: 06:55pm 11 May 2017

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Yes, I mean the clearance from the pad.

Smoke makes things work. When the smoke gets out, it stops!

MicroBlocks

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Joined: 12/05/2012
Location: Thailand
Posts: 2209

Posted: 07:24pm 11 May 2017

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I actually shrink the soldermask so that the pad is slightly covered with soldermask.
Especially for QFN/SSOP's this gives some more soldermask between the pins which prevents bridging.
I shrink it between 0.05mm for qfn up to 0.1mm for the 1206 SMD parts.

Microblocks. Build with logic.

Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9746

Posted: 01:21am 12 May 2017

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Okey dokey, thanks for that info.

My boards are setup for 0.1mm for SMD, and 0.3mm for pads. I will shrink the pad figure, as it has been wiping out some silkscreen I would like to get closer to the pads.

Smoke makes things work. When the smoke gets out, it stops!

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